A small town in northern Italy began a trial of blanket testing its 3,300 residents and imposing strict quarantines on those infected, and their contacts, when the pandemic started in Europe.

On Wednesday the mayor of Vo, near Venice, said the town had not registered any new cases since Friday.

"Testing was vital, it has saved many lives," mayor Giuliano Martini was quoted by the country's media.

Image:Italian soldiers patrol by a check-point at the entrance of the small town of Vo Vecchio, situated in the red zone

Andrea Crisanti, an infections expert at Imperial College London, who has been involved in the village's efforts to combat the virus told Italy's broadcast media that continuous testing and retesting of the whole population made the difference.

Professor Crisanti said: "In Vo Euganeo we tested all the inhabitants, even those who were asymptomatic.

"All citizens were put in isolation, so they could not transmit the disease.

"On the second testing that was carried out, we recorded a 90% drop in the rate of positive cases. And of all the ones who were positive in the second testing, eight people were asymptomatic."

Image:A man wearing a protective mask on an empty Rialto Bridge in Venice during the lockdown

The World Heath Organisation (WHO) this week called on all countries to ramp up testing programmes as the best way to slow the advance of the pandemic.

WHO Director General Tedros Adhanom Ghebreyesus said: "We have a simple message to all countries - test, test, test.

"All countries should be able to test all suspected cases. They cannot fight this pandemic blindfolded."